Sequential Sampling Plan of Anthonomus grandis (Coleoptera: Curculionidae) in Cotton Plants

Abstract

The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is one of the most important pests of cotton production worldwide. The objective of this work was to develop a sequential sampling plan for the boll weevil. The studies were conducted in Maracaju, MS, Brazil, in two seasons with cotton cultivar FM 993. A 10,000-m2 area of cotton was subdivided into 100 of 10- by 10-m plots, and five plants per plot were evaluated weekly, recording the number of squares with feeding + oviposition punctures of A. grandis in each plant. A sequential sampling plan by the maximum likelihood ratio test was developed, using a 10% threshold level of squares attacked. A 5% security level was adopted for the elaboration of the sequential sampling plan. The type I and type II error used was 0.05, recommended for studies with insects. The adjustment of the frequency distributions used were divided into two phases, so that the model that best fit to the data was the negative binomial distribution up to 85 DAE (Phase I), and from there the best fit was Poisson distribution (Phase II). The equations that define the decision-making for Phase I are S0 = -5.1743 + 0.5730N and S1 = 5.1743 + 0.5730N, and for the Phase II are S0 = -4.2479 + 0.5771N and S1 = 4.2479 + 0.5771N. The sequential sampling plan developed indicated the maximum number of sample units expected for decision-making is ∼39 and 31 samples for Phases I and II, respectively.

Morphological Characteristics and Occurrence of an Important Stem-Boring Pest, Nassophasis sp. (Coleoptera: Rhynchophorinae)

“…Regarding distribution of Nassophasis sp., the insects were aggregated in the forest and shed, and the intensity of aggregation increased with increasing population density. This distribution pattern is the same as Lissorhoptrus oryzophilus [21], Anthonomus grandis [22], and Cosmopolites sordidus [23]. Upon analysis, the aggregation of Nassophasis sp.…”

Infestation of Anthonomus grandis grandis (Coleoptera: Curculionidae) contributes to forming shelter structures in cotton plants

“…The relationship between boll weevil population density and damaged cotton reproductive structures (da Silva et al., 2017; Greenberg et al., 2003; Grigolli et al., 2017) is enhanced by the overlapping of generations synchronized with the phenological development of the cotton plants (da Silva et al., 2017; Showler et al., 2005). In this study, the number of green bolls was reduced in plants infested with the boll weevil throughout the evaluations, more severely in treatments with greater density of the insect.…”

Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae) induces the formation of shelter structures in cotton plants

“…Variability in the number of ower buds and bolls between treatments indicates a relationship between the weevil population density and damage to cotton reproductive structures (Greenberg et al 2003, Grigolli et al 2017, Silva et al 2017, which is enhanced by the overlapping of generations synchronized with the phenological development of the cotton plant (Showler et al 2005, Silva et al 2017. Injuries caused by weevils lead to abscission of ower buds and small green apples.…”